The Pothole Index

Author(s):

Alan Hoogasian, Research Economist

Published:

04-23-2015

So you think the roads are rough in Tucson? Well, you are correct! Compared to 11 western urban areas Tucson had the highest pothole index in 2012, at 145.8. Since the U.S. urban area average was 100.0, the index implies that Tucson’s roads were 45.8% rougher than the U.S. urban area average.

Tucson’s high Pothole Index arose because our other principal arterial roads are rough and they get a large share of traffic, compared to other urban areas. Other principal arterials are heavily used urban roads that collect traffic from intersecting residential streets, and direct it toward employment or business centers, or other travel routes such as freeways and interstates. Examples for Tucson are Grant Road, Speedway Boulevard, and Broadway Boulevard. In 2012, the Federal Highway Administration (FHWA) estimated that 38.9% of our other principal arterials rated poor. That is a very big deal, because 49.2% of local vehicle miles traveled were on other principal arterials (the largest share of any of the 12 western urban areas).

The roads in San Diego, Colorado Springs, and Denver were also far above the U.S. urban average.

Where are the smooth roads? Just head up to Phoenix, which had the lowest index in 2012. Indeed, the Phoenix Pothole Index was 81.3% below the U.S. average. Austin, Salt Lake City, Las Vegas, El Paso, Portland, San Antonio, and Albuquerque were also below the U.S. average in 2012.

The Pothole Index accounts for both the roughness of major roads within each urban area (by road type) and the degree to which those roads are used by local drivers. Thus, a very rough road type which gets a lot of traffic will tend to increase the Pothole Index for an urban area. In more technical terms, we weight the share of major roads (by road type) rated poor by the Federal Highway Administration by the vehicle miles traveled on those roads. To see the underlying data, check out “Rough Roads”.